Fluid pressure controlling and reversing mechanism for grinding machines and the like



Nov. 17, 1931. A. M. DRAKE ET AL 1,832,365

FLUID PRESSURE CONTROLLING AND REVERSING MECHANISM FDR GRINDING MACHINESAND THE LIKE Filed Jan. 9, 1922 2 Sheets-Sheer l Nov. 17, 1931. A. M.DRAKE ET AL 1,832,365

FLUID PRESSURE CONTROLLING AND REVERSING MECHANISM FOR GRINDING MACHINESAND THE LIKE Filed Jan. 9. 1922 2 sheets-Sheet 2 iarniiqj Patented Nov.17, 1931 UNITED STATES PATENT OFFICE ALDEN M. DRAKE AND BAY D. HUBBELL,OF WORCESTER, MASSACHUSETTS, ASSIGNOBS TO THE HEALD MACHINE COMPANY, OFWORCESTER, MASSACHUSETTS, A CORPO- RATION OI MASSACHUSETTS FLUIDPRESSURE CONTROLLING AND REVERSING MECHANISM FOR GRINDING- MACHINES ANDTHE LIKE Application filed January 9, 1922. Serial No. 528,118.

The present invention relates to fluid pressure mechanism forcontrolling and reversing the movements of reciprocatory machineelements,being here shown and described, b way of example, in connectionwith a grin ing machine table. The invention, however, is susceptible ofapplication to numerous other and different uses, wherein fluid underpressure, throu h the common form of a hydraulic cylin er and pistondevice, is emplo ed as the actuating medium to procure an control thereciprocatory movements of various parts of machinery.

The features of the invention are fully set forth hereinafter, referencebeing had to the accompanying drawings, wherein- Fig. 1 is adiagrammatic view of a fluid pressure actuating system applied to thetable of a grinding machine, and showing our invention in connectiontherewith.

Fig. 2 is an exterior view, in side elevation, of the control mechanismfor the fluid pressure system.

Fig. 3 is a similar view, with certain parts broken away, or removed, todisclose the interior arrangement.

Fig. 4 is a transverse sectional view of said control mechanism.

Fig. 5 is a sectional view on the line 5-5 of Fig. 4, showing the valvepassages for the fluid pressure medium.

Fig. 6 is a detail view of the oscillating valve member.

Fig. 7 is a detail view of the valve cap or closure. Figs. 7a and 7 bare diagrammatic views of the valve ports and associated passages, andshown respectively in neutral and in one operative position.

Fig.8 is, a fragmentary detail view of certain of the parts shown inFig. 2.

Fig. 9 is a fragmentary detail view of certain of the parts shown inFig. 4.

Like reference characters refer to like parts in the different figures.

Referring first to Fig. 1, there is shown, diagrammatically, a fluidpressure cylinder 1, the latter containing the usual double actingpiston 2 which is suitably connected, as by red 3, with the element 4 tobe reciprocated,--

here shown as the table of a grinding machine, which table is slidablein ways 5, 5, (Figs. 4 and 8) provided by the machine framework. Thepiston 2 is actuated by the admission of a fluid under pressure to oneend or the other of the cylinder 1, said pressure fluid being forced bypump 6 into a supply pipe 7, the latter leading to a valve device 8, theposition which, as hereinafter described, determines the admission offpressure medium to one end or the other 0 cylinder 1, by way of pipe 9or pipe 10, as the case may be.

Said pressure medium makes its return to the pump from the cylinder byway of exhaust pipe 12, leading directly from the valve device 8 to thesupply tank. By the arrangement of mechanism above described, the

movement of table 4 is obtained, it being understood that travel in eachdirection of the piston 2 is directly under the control of the valvedevice; the movement of the latter into its different positionsprocuring, in the manner well known in the grinding machine art, thestarting, stoppingand reversal of the pressure actuated devices.

The valve device 8 is shown most clearly in Figs. 5, 6 and 7 7a and 7 band its appurtenant parts, whereby its actuation is controlled by theoperator and by the movement of the table, are shown in Figs. 2, 3 and4. These parts are conveniently disposed in a casting bolted to thefront of the machine frame, said casting providing a passage 16 to thevalve member proper from the fluid pressure supply pipe 7. The passage16 is provided with a rotatable throttle valve 17, the latter having acutaway portion 18 where it crosses the passage 16, as shown in Figs. 4and 5. The valve 17 is adapted to be manlpulated by a handle 19, thelatter swinging over a scale 20 into different positions, indicative ofa greater or less flow of pressure medium through the passage 16,whereby to speed up or slow down, as desired, the reciprocations of thepiston 2.

The passage 16 opens into a stationary member 21, Figs. 4 and 5,constituting a seat for the rotatable reversing valve 8, hereinbeforereferred to. Said seat 21 has one recess 22 in constant communicationwith passage 16and a separate independent recess 23 in constantcommunication with the return pipe 12 to the supply tank. Theoscillating valve 8, as shown in Fig. 6, has three apertures, 24a, 24band 240 therethrough; in the right hand extreme position of the valvehandle, the aperture 24a connects seat recess 22 with the opening 25 inend closure cap 26, Figs. 4, 5 and 7, making direct connection frompassage 16 to the left hand cylinder supply pipe 9, as showndiagrammatically in Fig. 76. At the same time aperture 241) connects theopening 27 in end cap 26 with the recess 23 in valve seat 21, thusmaking a direct connection from the right hand cylinder pipe 10 toexhaust pipe 12, as shown diagrammatically in Fig. 7 6. Under theseconditions, the pressure fluid passes from the pump through the valve 8and the left hand pipe 9, driving the piston 2 and thereby the table 4to the right, the fluid in the right hand end of the cylinder escapingthrough pipe 10, opening 27, aperture 24b, recess 23 and pipe 12 to thesupply tank.

In the extreme left hand position of the valve handle, i. e., thereverse position from that illustrated in Fig. 7 b, the aperture 24aconnects recess 22 with the opening 27 in the end cap 26, making adirect connection from passage 16 to the right hand cylinder supply pipe10, thus forcing the piston to the left. The fluid in the left hand endof the cylinder returns to the tank through pipe 9, openings 25, 24c,recess 23 and pipe 12.

In the intermediate or neutral position of the valve 8, as showndiagrammatically in Fig. 7a, connection is made from recess 22 throughaperture 24a to both ports 25 and 27 and also around the partitions invalve 8 to recess 23 and return pipe 12. In this neutral position, thenarrow partition between valve apertures 24a and 24b 15 across the capopening 27, but does not completely cover it, and the similar narrowpartition between apertures 24a and 240 is across the cap opening 25 andlikewise does not completely cover it; thus the valve 8 in this neutralposition establishes direct communication between the inlet seat recess22 and the outlet seat recess 23. This gives what may be called ableeding valve, as it allows the fluid to be pumped around through thesupply pipe 7 and return pipe 12 without building up an excessivepressure. In other words, the flow of fluid, in this neutral position,is not discontinued, as is the case in certain prior constructions, andconsequently, the relief valve 13 on the pump 6 is called upon for muchless service than would otherwise be the case, so that a smaller valvewill suflice.

Since the pressure is equal in this neutral position through the ports25 and 27 no effort is exerted by the fluid to move the table, which isthus in a balanced condition. This secures the further advantage that ifit should be desirable to move the table at any time by a hand wheel, orother mechanical means, the fluid is not locked in the cylinder by thevalve, but can pass out freely in either direction so that in theneutral position of the valve, as illustrated diagrammatically in Fig. 7a, the table can be moved freely in any way desired.

The shaft 28 of valve 8 has its free end projecting into a lubricantcontaining box 29, mounted on the front of casting 15, and said free endhas secured thereto a block 30. The block 30 has a downward projection31 which works between a pair of fixed spaced stops 32, 32, which limitthe oscillation of valve 8 on its axis in both directions. The stops 32have alined opposing openings 63, 63 for a plunger 62, these openingsbeing closed at their outer ends by screw caps 64, 64, each having asmall bleed hole. The plunger 62 is made smaller in the middle toreceive the end 31 of the block 30, and it serves to control the speedat which the valve 8 swings over, producing a dash-pot efi'ect at eachend of the travel of the valve.

At right angles to the axis of the valve shaft 28 are provided trunnions33, 33 for the pivotal attachment of a control lever 34, having a knobin convenient reach of the operator. A spring 37, disposed in a suitablerecess of the lever 34, yieldingly maintains said lever in the positionillustrated in Fig. 4, whereby an inwardly projecting pin 38 of saidlever is normally disposed in a notch 39 of an oscillating segment 40,Fig. 3. When the knob 36 of direction control lever 34 is depressed,against the force of spring 37, the rocking of lever 34 about thetrunnions 33 withdraws the pin 38 from notch 39, thereby freeing thelever 34 from the segment 40, and allowing the valve shaft 28 to berocked by hand in either direction.

The oscillating segment 40 is pivoted on a shaft 41, and is recessed onits rear side to provide a slideway for pin 42, which, as

shown in Fig. 9, has its end enlarged in triangular form to provideflattened angular surfaces for cooperation with similar surfaces of astationary member 43. The pin 42 is held in contact with the member 43by a spring 44; the movement of oscillating segment 40 in eitherdirection, causes the pin 42 to recede in its socket, thus distendingthe spring 44, and as said pin is carried over dead center, the spring44. acts to carry the segment 40 through the last half of its movementwhich proeures the reversal of valve 8.

As shown in Fig. 2, the segment 40, above its pivotal point, has aprojection 45, the latter adapted to be engaged by stops or table dogs46, 47 and 48, such as are usually carried by a grinding machine table.or other reciprocating machine element. The stops or dogs 46 and 47 arehere indicated as those which are ordinarily adjustable, along the edgeof the table, to engage the projection alternately, whereby to reversethe direction of travel at each engagement and to fix the throw orlength of table travel, for any given operation. The third stop or dog48 s adapted to be engaged by the projection 45 at the outer limit ofthe return movement of the table, in order to bring said table to restat this point. In the normal operation of the mechanism, the stops 46and 47 bein set the desired distance apart, the travel 0 the table 4 tothe left, Fig. 2, brings the stop 46 ultimately against the projection45, rocking the segment 40 in a counterclockwise direction and causingthe notch 39, b its engagement with pin 38, to throw the irectioncontrol lever 34 to the right; this movement, being continued by thespring pressed pin 42, rocks the valve shaft 28, causing the valve 8 toreverse, and admit ressure medium to the other or left hand side ofpiston 2. Coincident with this shifting of the direction control leverto the right, the table begins to move in the right hand direction,ultimately bringing the stop 47 against the projection 45, so as to rockthe segment 40 clockwise; this in turn, in the manner above described,rocks the direction control lever to the left, thereby reversing thevalve again and causing admission of pressure medium to the right handside of piston 2.

If for any reason it is desired to interrupt or change in any way thisnormal automatic operation of the mechanism, the operator has merely toseize the handle 34 of the direction control lever and depress the sameso as to remove the pin 38 from its notch 39; and then he is at libertyto move it to neutral to stop the motion of the table, or secure itsimmediate reversal, although this last mentioned function can be securedwithout withdrawing pin 38. When handle 34 is depressed, with thesegment 40 at either end of its travel, the pin 38 rests on the surface35 of segment 40 when in neutral position, and will remain there withthe table stationary until handle 34 is thrown in either direction, atwhich time the table will immediately begin to move in that samedirection. lVhichever direction is selected, the normal position of theparts is automatically restored, either immediately or after the firstreversal of segment 40, by cooperation of the pins 49, projecting fromthe face of the segment 40, which engage the lever 34 to move it intothe position of registration of pin 38 with notch 39.

The projection 45, as ordinarily made, is bevelled away at the upperend, as shown in Fig. 2, to make it possible for the stop 47 to passover said projection, when it is desired to procure the full right handmovement of the table for the purpose of inspecting or gauging the work.Under these conditions, the lever 34 is depressed as the table moves tothe right, and as the stop 47 acting upon E'o]ect1on 45 does not reversethe valve 8 cause pm 38 has been withdrawn from notch 39, the tablecontinues to move to the right, segment 40 swinging over till stop 47passes over projection 45. Finally the stop strikes projection 45,whereupon the segment 40 is rocked sufliciently so that pin 50 forceslever 34 to a vertical and thereby neutral position, thus stopping thefurther motion of the table.

This extended movement, taking place While no work is being done, neednot occur at the relatively slow speed of the working strokes; for thisreason, it is proposed, in

order to save time, that such movement be at the maximum speed of thetable, irrespective of the setting of speed control lever 19. As shownin Figs. 2 and 8, the stop 47 carries a bar 51, the latter adapted toengage the upper end of a rocking lever 52 immedlately after stop 47 haspassed over projection 45. The lever 52, as shown in Fig. 8, has apivoted stud 53 to which is secured an arm 54. The engagement ofprojection 51 with the end of lever 52 may be obtained or not, asdesired; the end of said lever, as shown in Fig. 8, has a transversebore in which is received a plunger 55, the latter carrying a portion 56which, when the plunger is withdrawn to its outer limit as shown in Fig.8, stands in the path of the bar 51. In this position of the plunger,the engagement of the bar 51 is assured; when the plunger is pushed in,however, no engagement takes place and there is no change in the speedof the table as it moves to its extreme outward position.

The depending arm 54 is acted upon by spring 57, which maintains the endof lever 56 in the path of rojection 51, and also yieldingly urges to te right, Fig. 2, a slidable member 58, to which the lower end of arm 54is yoked. The slidable member 58 enters the casting 15 containing thevalve mechanism, and its bore intersects a passage. 59, parallel to thepassage 16, and by-passing the speed control valve 17, as shown in Figs.1, 2 and 5. The member 58 in its normal position, as illustrated inFigs. 2 and5, closes this passage 59; however, when the lever 52 isrocked by engagement therewith of the projection 51, said member 58 isforced inwardly, bringing a passage 60 thereof into register with theby-pass 59. This admits the full unthrottled supply of pressure. fluidto the valve 8, irrespective of the position of speed control valve 17and thus allows the outward movement of the table to take place atmaximum speed until it is finally brought to rest at-the limit of saidoutward movement by the'operation of do 48 bringing lever 34 to a middleor neutra position.

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In this way no time is lost in rendering the work available forinspection or gauging by the operator. Furthermore, no time is lostbringing about a resumption of the automatic reciprocations of thetable, since the operator has merely to throw the direction controllever 34 to the left, whereupon the table will immediately start in thesame d1 rection also at maximum speed, the passage 60 still being inregister with the by-pass 59. However, as soon as the stop 47 has movedpast the projection 45, the engagement of bar 51 with lever 52 ceases,and the parts return to normal operation, so that the regular workingreciprocations of the table as de termined by the distance between thestops 46 and 47 are resumed at once at the throttled down speedcontrolled by lever 19 and valve 17 It is to be noted that thisrestoration of normal operation takes place automatically, as thereduction in speed is also effected without the necessity of, anyintervention by the operator, except to start the table by moving thecontrol lever or handle 34 in the first named -instancetherebydistinguishing from previous constructions wherein the increased ormaximum speed on this withdrawa1 movement of the table is obtainable bythe manual operation of a fluid pressure by-pass valve. With such priorconstructions, the operator must exercise extreme care, as the table onits return movement approaches the work, and must make sure that themaximum speed of the table is discontinued, before operation on the workis resumed. According to the present construction, the. necessity forthis watchfulness is eliminated, since the speed of the table isthrottled automatically at the instant that the bar 51 moves off oflever 52.or just before the regular working stroke of the table isresumed.

We claim 1. Apparatus of the class described, comprising a tablereciprocable by fluid under pressure. a reversing valve'for the pressurefluid, adjustable stops on said table for operating said valve, toprocure the reversals of said table, and means for adjusting the flow ofpressure fluid to control the speed of said table, in combination withan operating lever for said valve, said lever in its normal positionbeing actuated by said stops, means responsive to deflection of saidlever from said normal position for causing the inoperative traverse ofone of said stops, and means responsive to the ensuing movement of saidtable, beyond the normal reciprocatory path determined by said stops,for rendering said speed adjusting means ineifective.

2. Apparatus of the class described, comprising a table reciprocable byfluid under pressure and carrying adjustable valve-operating stops, anda reversing valve for the pressure fluid, actuated alternately by saidstops, to change the direction of travel of said table, in combinationwith an operating lever for said valve adapted in its normal position totransmit thereto the motions imparted by said stops, said lever beingmovable, without disconnection from said valve, from said normalposition, to discontinue the operation of said valve by one of saidstops, thereby procuring the travel of said table be yond thereciprocatory path determined by said stops.

3. In apparatus of the class described, a reciprocating element actuatedby fluid pres sure, a reversing valve for the pressure fluid, and alever by which said valve is moved, in combination with a swingingmember engageable by dogs on said element, and having a connection withsaid valve lever adapted to be rendered inoperative to permit independent movement of the latter, and means carried by said member forautomatically restoring said connection.

4. In apparatus of the class described. a reciprocating element-actuatedby fluid pressure and having a predetermined working stroke. a throttlevalve for the pressure fluid to control the speed of said element, andmeans for automatically by-passing said throttle valve when said elementis moved to and from its working position.

In apparatus of the class described, a reciprocating element actuated byfluid pressure and having a predetermined working stroke, a throttlevalve for the pressure fluid to control the speed of said element, meansfor procuring movement of said element at maximum-speed, unaffected bysaid throttle valve, when travelling toward its working position, andmeans responsive to the travel of said element for automaticallydiscontinuing said maximum speed, in advance of the resumption of saidworking stroke.

6. In apparatus of the class described, a reciprocating element actuatedby fluid pressure and having a predetermined working stroke. a throttlevalve for the pressure fluid to control the speed of said element, meansfor procuring movement of said element at maximum speed, unaffected bysaid throttle valve when travelling away from its working position, andmeans responsive to travel of said element toward its working positionfor automatically discontinuing said maximum speed in advance of theresumption of said working stroke.

7. A grinding machine having, in combination, a carriage having an idleposition and a position in whichit reciprocates, a piston and cylinderunit for moving said carriage, a control valve connected to a source ofpressure fluid and to said piston and cylinder unit, a valve operatingdevice, means on said carriage for moving said device when the carriageis in its reciprocating position to automatically reverse said valve andeffect reciprocation of said carriage, and means on the carriage foroperating said device when the carriage is at its idle position to movesaid valve to its neutral or inactive position and thereby stopreciprocation of said carriage.

8. A grinding machine having, in combination, a slidably mountedcarriage, pressure fluid means for reciprocating said carriage includinga control valve, a lever for operating said valve, and a stop on saidcarriage arranged to engage said lever and move said valve to neutralposition to discontinue the movement of said carriage.

9. A grinding machine having,in combination, a reciprocatorycarriagehaving an idle position and an operative position, pressure fluid meansfor moving said carriage includ ing a control valve, an operating devicefor said valve, means on said carriage to actuate said operating devicewhen the carriage approaches its idle position to move the valve toneutral position, and separate means on said carriage whichautomatically comes into operative relation to said 0 erating device inthe movement of said carnage from idle to operative position forautomatically reciprocating said operating device to reverse saidcontrol valve and thereby efiect continuous reciprocation of saidcarriage in its operative position.

10. A machine of the character described having, in combination, acarriage having an operative position and an idle position remote fromsaid operative position, and mechanism arranged to reciprocate thecarriage in its operative position to return the carriage to its idleposition and to automatically stop the carriage at its idle position.

11. In a grinding machine, a grinding wheel, a slidably mounted carriagehaving reciprocator movement in its working position, to pro uce arelative grinding traverse between the work and said wheel,-speed-controlling means efi'ective on said carriage in said workingposition, and means set in operation by travel of said carriage awayfrom said working position to render said speedcontrolling meansineffective on said carriage for substantially the length of saidtravel.

12. In a grinding machine, a grinding wheel, a slidably mountedcarriage, means for reciprocating said carriage at apredetermined speedin its working position, to produce a relative grinding traverse betweenthe work and said wheel, means for extending the movement of saidcarriage in one direction, to effect separation of wheel and work, andmeans brought into action by said extended carriage movement forincreasing the speed of said carriage.

13. In a rinding machine, a slidably mounted carnage having a workingposition and an idle position, means for reciprocating said carriage insaid working osition at an adjusted speed, and means ma e effective bytravel of said carriage between said two positions for establishing ahigher carriage speed, without disturbance of said speed adjustment.

14. In a grinding machine, a slidably mounted carriage having a workingposition and an idle position, means for reciprocating said carriage insaid working position at an adjusted speed, means made effective bytravel of said carriage between said two positions, for establishin ahigher speed without disturbance of sa1d adjustment, and means operativeat a predetermined point in the travel of said carriage from idleposition toward said working position, for restoring said adjustedspeed.

15. In a grinding machine, a slidably mounted carriage having a workingposition and an idle position, fluid pressure means for moving saidcarriage, reversing devices cooperating with said fluid pressure meansfor reciprocating said carriage in said working position, a throttlevalve to control the spec of said working reciprocations, means fordisabling said reversing devices, thereby to make sa1d fluid pressuremeans effective for the movement of said carriage awa from workingposition, and means broug t into action by said last named movement forren-- dering said throttle valve inefl'ective, thereby to procure travelof said carriage to its idle position at an increased speed.

v 16. In a rinding machine, a grindin wheel, a slidably mountedcarriage, fiui pressure means for reciprocating said carriage in itsworking osition, to traverse the work with said whee a throttle valveeffective on the pressure fluid to control the speed of said workingreciprocation, means for extending the movement of said carria e in onedirection, to eflect separation of w eel and work, and a by-pass for thepressure fluid, around said throttle valve, said by-pass being opened bysaid extended movementof said carriage, to increase the latters speedwhen wheel and work are separated.

Dated this 4th day of January, 1922.

ALDEN M. DRAKE. RAY D. HUBBELL.

